Stormwater runoff can contain high amounts of Potential Toxic Elements (PTE) as heavy metals. PTE can have negative and direct impact on the quality of surface waters and groundwater. The European Water Framework Directive (WFD) demands enhanced protection of the aquatic environment. As a consequence, the WFD requires municipalities and water authorities to address the emissions from drainage systems adequately and to take action when these emissions affect the quality of receiving waters together with mitigating the quantity challenges in a changing climate (floodings and drought). NBS is the most widely used method for storing stormwater and infiltrating in the Netherlands. However, there is still too little knowledge about the long-term functioning of the soil of these facilities. The research results are of great importance for all stakeholders in (inter)national cities that are involved in climate adaptation. Applying Nature-Based Solutions (NBS), Sustainable Urban Drainage Systems (SuDS) or Water Sensitive Urban Design (WSUD) are known to improve the water quality in the urban water cycle. The efficiency of NBS, such as the capability of bio swales to trap PTE, highly depends on the dimensions of the facility and on its implementation in the field [Woods Ballard, B et al, 2015]. For the determination of the removal efficiency of NBS information about stormwater quality and characteristics is essential. Acquiring the following information is strongly advised [Boogaard et al. 2014]:1. stormwater quality levels (method: stormwater quality database);2. location of NBS (method: mapping NBS in international database);3. behaviour of pollutants (method: cost effective mapping pollutants in the field). Stormwater quality contains pollutants as heavy metal in higher concentrations than water quality standards dictate. Over 500 locations with bio swales are mapped in the Netherlands which is a fraction of stormwater infiltration locations implemented in 20 years’ time. Monitoring of all these NBS would acquire high capacity and budget from the Dutch resources. This quick scan XRF mapping methodology of topsoil will indicate if the topsoil is polluted and whether the concentrations exceed national or international standards. This was only the case in one of the youngest pilots in Utrecht indicating that there are multiple factors other than age (traffic intensity, use of materials, storage volume, maintenance, run off quality, etc.). Several locations show unacceptable levels, above the national thresholds for pollutants where further research on the prediction of these levels in relation to multiple factors will be the subject of future research.The results of study are shared in 2 national workshops and valued as of great importance for all stakeholders in (inter)national cities that are involved in implementation of NBS for climate adaptation. The Dutch research results will be used to update (inter-)national guidelines for design, construction and maintenance of infiltration facilities this year. Stormwater managers are strongly advised to use this quick scan method within the first 10 years after implementation of swales to map possible pollution of the top soil and prevent pollution to spread to the groundwater in urban areas.
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Sustainable urban drainage systems (SuDS) such as swales are designed to collect, store and infiltrate a large amount of surface runoff water during heavy rainfall. Stormwater is known to transport pollutants, such as particle-bound heavy metals, which are known to often accumulate in the topsoil. In this study, a portable XRF instrument is used to provide in situ spatial characterization of soil pollutants. The method uses portable XRF measurements of heavy metals along profiles with set intervals (1 meter) to cover the swale with cross-sections, across the inlet, the deepest point and the outlet. Soil samples are collected, and the In-Situ measurements are verified by the results from laboratory analyses. Stormwater is here shown to be the transporting media for the pollutants, so it is of importance to investigate areas most prone to flooding and infiltration. This quick scan method is time and cost-efficient, easy to execute and the results are comparable to any known (inter)national threshold criteria for polluted soils. The results are of great importance for all stakeholders in cities that are involved in climate adaptation and implementing green infrastructure in urban areas. However, too little is still known about the long-term functioning of the soil-based SuDS facilities.
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'Versteende pleinen in steden zijn hitte-eilanden. Gemeenten willen daarom meer groen, maar dat is niet eenvoudig. In Groningen zijn nieuwe bomen geplant in een innovatief waterbergingssysteem. De Grote Markt ging op de schop.'
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Tijdens het rioolsymposium op 11 maart 2022 stond Floris Boogaard stil bij de 'vergroening' van het riool. De conferentie vond plaats ter gelegenheid van de afronding van de omvangrijke werkzaamheden aan het hoofdriool in Arnhem. Bezocht door ongeveer honderd mensen uit Nederland, België en Duitsland.
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Kunnen wadi’s en raingardens overal? Hoe regel je het beheer? Wat is de ecologische waarde van een wadi of raingarden? Hoe overtuig ik de gemeente? In sneltreinvaart toont Floris Boogaard (Hanzehogeschool Groningen en Deltares) honderden inspirerende voorbeelden. Hij geeft daarmee antwoord op de meest gestelde vragen over wadi’s en raingardens: het kan (bijna) overal en de woonomgeving wordt er leefbaarder van.
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BackgroundThe challenge of combining professional work and breastfeeding is a key reason why women choose not to breastfeed or to stop breastfeeding early. We posited that having access to a high-quality lactation room at the workplace could influence working mothers’ satisfaction and perceptions related to expressing breast milk at work, which could have important longer term consequences for the duration of breastfeeding. Specifically, we aimed to (1) develop a checklist for assessing the quality of lactation rooms and (2) explore how lactation room quality affects lactating mothers’ satisfaction and perceptions. Drawing on social ecological insights, we hypothesized that the quality of lactation rooms (operationalized as any space used for expressing milk at work) would be positively related to mothers’ satisfaction with the room, perceived ease of, and perceived support for milk expression at work.MethodsWe conducted two studies. In Study 1 we developed a lactation room quality checklist (LRQC) and assessed its reliability twice, using samples of 33 lactation rooms (Study 1a) and 31 lactation rooms (Study 1b). Data were collected in the Northern part of the Netherlands (between December 2016 and April 2017). Study 2 comprised a cross-sectional survey of 511 lactating mothers, working in a variety of Dutch organizations. The mothers were recruited through the Facebook page of a popular Dutch breastfeeding website. They completed online questionnaires containing the LRQC and measures aimed at assessing their satisfaction and perceptions related to milk expression at work (in June and July 2017).ResultsThe LRQC was deemed reliable and easy to apply in practice. As predicted, we found that objectively assessed higher-quality lactation rooms were associated with increased levels of satisfaction with the lactation rooms, perceived ease of milk expression at work, and perceived support from supervisors and co-workers for expressing milk in the workplace.ConclusionsThe availability of a high-quality lactation room could influence mothers’ decisions regarding breast milk expression at work and the commencement and/or continuation of breastfeeding. Future studies should explore whether and how lactation room quality affects breastfeeding choices, and which aspects are most important to include in lactation rooms.
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In this book of examples we present possible implementations of straightforward and manageable climate-resilient ideas and options for residential streets. Examples from ordinary Dutch street views show how climate resilience can be implemented with simple solutions and how this does not need to be more costly than traditional measures, particularly in flat areas (such as we often find in the Netherlands). This observation is based on comparative studies across various Dutch cities. We hope that the examples will inspire you to find ways to implementclimate-resilient measures in your city, because the climate is right up your street.
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Recent years have seen a global rise in the failure of tailings dams. Studies investigating the causes of slope failure often recognise high intensity rainfall events to significantly contribute to liquefaction, erosion and overtopping. This study aims to investigate the influence of alternative physical and geohydrological processes that, under tension saturation conditions, contribute to slope instability in tailings dams. It has been suggested that the generation of transient pressure wave mechanisms by high intensity rainfall events, surface ponding and wetting front advancement result in the formation of an induced pressure head that triggers the mobilization of pre-event water. In order to quantify these physical processes, this study included the analysis of rapid transmission conditions in a silica fines mix, with similar physical and hydraulic characteristics as platinum tailings. A tall leak-proof soil column, containing the soil sample compacted to in-situ dry bulk density, was fitted with seven observation ports. Each port consisted of a pore air pressure probe, a mini tensiometer and a time domain reflectometry probe. After set-up and initial stabilisation, three separate artificial high intensity rainfall events were applied to the surface. Monitoring of hydraulic state variables was recorded at thirty second intervals by automatic logging, thereby enabling the analysis of measured outcomes. Observations showed instant spikes in pore air pressure ahead of the wetting front, as well as a number of delayed responses. The interpretation of lab results led to the conclusion that pressure diffusion mechanisms throughout the porous medium, could result in the rapid release and mobilisation of previously stagnant antecedent moisture, thereby enabling phreatic levels to rising rapidly and in excess to the amount of surface infiltration. Also, since an increase in pore water pressure is likely to cause a reduction in shear strength, it is suggested that these physical and geohydrological processes could have an adverse impact on the stability of tailings dams.
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This CIENS-report sums up the main findings from the project “Cultural heritage and water management in urban planning” (Urban WATCH), financed by the Research Council of Norway through the MILJØ2015 programme, and cofunded by the Directorate for Cultural Heritage in Norway (Riksantikvaren) and the Geological Survey of Norway (NGU). The project started up in 2012 and ended in 2015.
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The results obtained in this study are encouraging and important for the implementation of permeable pavement and swales in The Netherlands, since the performance of SUDS in delta areas and in areas in the world with comparable hydraulic circumstances has been viewed with skepticism. The research undertaken on Dutch SUDS field installations has demonstrated with new, full scale monitoring methods that most of the bioretention swales and permeable pavements tested in this study meet the required hydraulic performance levels even after years in operation and without maintenance. Standardized tests of sedimentation devices however demonstrated that these facilities have a limited effectiveness for particles smaller than 60 µm while receiving a normal hydraulic loading. The applied methods of full scale testing of SUDS can easily be applied to observe the hydraulic performance of swales and permeable pavement after years of operation. Innovative monitoring methods and visualization of these experiments using video footage allows real-time observation of the entire infiltration process. Recording these observations in a logbook can provide insight in their demand of maintenance and can also help to improve their design.
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